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In this work an Algerian natural bentonite was used in the preparation of new adsorbents by impregnation with different mass ratios of hexadecyltrimethylammonium bromide (HDTMA) surfactant. The HDTMA-bentonites adsorbents were prepared according to the HDTMA/bentonite cation exchange capacity (CEC) ratios (HDTMA/CEC). Five HDTMA/CEC ratios (25%, 50...
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... XRD spectra of HDTMA-0.25, HDTMA-0.5, HDTMA-1, HDTMA-1.5 and HDTMA-2 are presented in Fig. 4. The interlayer distance depends on the superficial electrical charge, the arrangement, and the concentration of HDTMA filling the interlayer space. The d 001 value of the Algerian bentonite, after intercalated with HDTMA at an HDTMA/ CEC ratio of 0.25, is equal to 13.2 A with a single reflection. When the HDTMA/CEC ratio is 0.5, there ...
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Activated biochar was prepared from water lily through combination of physical and chemical technique. The prepared adsorbent was characterized by thermogravimetric analysis (TGA), elemental analysis (CHN/O), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Brunauer-Emmett-Teller mo...
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... The second endothermic loss located between 130 and 680°C is caused by the slow loss of interlayer water and water coordinated with cations (−5.31 %) for bentonite [32]. Compared to Bentonite between 200 and 640°C, the degradation of HDTMA surfactant adsorbed with its counter-ion within the B is primarily responsible for the HDTMA-B's greater mass loss (−22 %) [33]. The dehydroxylation of Al-OH and Si-OH within the B structure is responsible for the final stage's mass loss of B and HDTMA-B being nearly identical (2.4 %) above approximately 670°C. ...
The adsorptive properties of the Erionyl Red (ER) dye on bentonite (B) intercalated with cetyltrimethylammonium bromide (HDTMA-B) were investigated using experimental and statistical physics methods. The dye was then taken up by the intercalated bentonite from a real water sample. After intercalation, X-ray diffraction analysis indicates an increase in HDTMA-B basal spacing to 15.2 Ả. Scanning electron microscopy images show the formation of large particles and many cavities. The results revealed that the material had high properties to adsorb organic molecules (greater than 99 %). The Langmuir-Freundlich model, described the isotherms, whereas the second-order model better captured the kinetic of dye adsorption. The maximum ER uptake observed was 478 mg g−1 at a temperature of 328 K. Reusability of nanocomposite showed stability, over five cycles. Thermodynamic analysis suggested spontaneous (negative ΔG°) and endothermic (positive ΔH°) adsorption processes. The statistical physics model was also used to estimate the orientation of ER adsorption on the material. The oxygens connected to the dye in the HDTMA-B structure played in particular an important role in the adsorption mechanisms of dye. This study combines experiment data with a theoretical approach to provide a new explanation for the mechanism. The removal of dyes from wastewater, in particular Erionyl red, is vital for the protection of the environment and public health. Nanocomposite appears to be an effective, durable, and environmentally friendly adsorbent for the removal of Erionyl red dye from synthetic solutions and real wastewater.
... This is due to the progressive development of continuous conductive channels in the polymer, which facilitates the transfer of electrical current. [36] Percolation threshold refers to the critical amount of conducting load required to produce the insulatingconducting transition. The electrical conductivity of polymeric materials is critically influenced by the homogeneous distribution of clay layers in the PVAC matrix. ...
Poly (vinyl acetate) (PVAC) based on Algerian clay maghnite was synthesized by an emulsion polymerization process in the present study. The prepared nanocomposites were analyzed by means of FTIR, UV‐visible, XRD, AFM, SEM, TGA and optical microscopy. The results obtained showed a semi‐crystalline structure of the composite system revealed by the XRD scheme. The addition of maghnite to the fillers up to 5 wt % has been shown to reduce the optical band gap energy, while the refractive index is greatly increased. The presence of maghnite in PVAC leads to an increase in surface roughness as measured by AFM analysis. The thermal stability of PVAC was significantly improved by the presence of maghnite in the polymer matrix. The mechanical test results indicate that the tensile strength of the polymer composites was improved by the increase in the concentration of clay platelets. The electrical property data show that as the frequency increases, the dielectric constant decreases and the electrical conductivity increases. The loading content of composites also influences their electrical and mechanical properties. This widens the range of applications for these materials in flexible electronics and in conductive coatings.
... In addition, we also identified several absorption bands as follows: 660 cm −1 (CH out of the bending plane), 1157 cm −1 (CO stretching), 1390 cm −1 (CH bending), 1458 cm −1 (CH 2 plane shearing), 2954 cm −1 (CH 2 symmetric stretching), respectively, as well as groups appearing around 1050-1300 cm −1 , corresponding to the C-O stretching vibration of the ester group. Data processing by FTIR spectra showed a good sequestration capacity and the strong interaction that exists between the clay and polymer [29]. ...
An in-depth study of polyvinylidene fluoride (PVDF) based nanocomposite systems will be the focus of this research. This polymer being hydrophobic and apolar, it will be unlikely to generate strong interactions with clay leaves called organophilic maghnite. The challenge of this study will therefore be to manage the load/polymer interfaces by using montmorillonite with specific surface treatments by adding a surfactant Cetyltrimethylammonium bromide. Therefore, a significant improvement in mechanical and thermal properties was observed. The properties of PVDFNC nanocomposites were evaluated using various physico-chemical techniques (XRD, FTIR, TGA, DSC, TEM, SEM). The results of the structural and thermal measurements carried out on these products reveal that the structural concept of the surfactant influences both the morphological profile, the thermal and mechanical properties of the nanocomposites obtained. Accelerated crystallization is observed in PVDNC nanocomposites as an effective nucleation agent, the crystals formed are predominantly β shaped and have a small number of polar α crystals. Measurements by X-ray diffraction, as well as transmission and scanning electron microscopy indicated that modified maghnite was perfectly distributed 3 % by weight in the polyvinylidene fluoride matrix. The mechanical properties of the nanocomposites were evaluated according to the filler material used and the polyvinylidene fluoride matrix.
... The equilibrium adsorption characteristics of IC onto biochar was explained by the adjustment of the experimental isotherms to Langmuir, Freundlich and Temkin models [74]. where q max (mg/g) represents the maximum amount within a monolayer and C e (mg/L) is the equilibrium concentration. ...
In this work, a local Algerian agricultural waste biomass, Ziziphus jujuba, was valorized into a new low-cost biochar (JB). The biochar was produced by a simple pyrolysis at 700°C for 1 h under an inert atmosphere and was used as a low-cost adsorbent to remove Indigo carmine dye (IC) from aqueous solution. The JB biochar was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman, pH pzc , and Brunauer-Emmett-Teller physico-chemical techniques. Adsorption studies were conducted using a batch process to study the effects of contact time, adsorbent amount, initial IC dye concentration, initial pH, ionic strength, and temperature. The Langmuir, Freundlich, and Temkin isotherm models were used to analyze equilibrium adsorption data, while the pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were used to analyze kinetic data. The equilibrium data was well fitted to the Freundlich isotherm with an R 2 value of 0.974. The theoretical maximum adsorption capacity was found to be 166.46 mg/g at 20°C according to the Langmuir model. The adsorption kinetic was found to follow the pseudo-first-order kinetic model. Thermodynamic study showed that the adsorption of IC onto JB biochar was feasible, spontaneous and endothermic.
... In addition, we also identified several absorption bands as follows: 660 cm −1 (CH out of the bending plane), 1157 cm −1 (CO stretching), 1390 cm −1 (CH bending), 1458 cm −1 (CH 2 plane shearing), 2954 cm −1 (CH 2 symmetric stretching), respectively, as well as groups appearing around 1050-1300 cm −1 , corresponding to the C-O stretching vibration of the ester group. Data processing by FTIR spectra showed a good sequestration capacity and the strong interaction that exists between the clay and polymer [29]. ...
A thermoplastic polyurethane (TPU) nanocomposite was synthesized based on Maghnite as an inorganic reinforcement phase. The result of this study was to evaluate the gas barrier properties of a thermoplastic polyurethane (TPU) material containing clay nanoparticles. The preparation of the thermoplastic polyurethane prepolymer with NCO terminations was carried out using an in situ solution polymerization method. The clay has already been modified by intercalation of 12-amino decanoic acid molecules NH2(CH2)11COOH (12-Mag). The polyethylene glycol/tolylene matrix 2,4-diisocyanate (PEG/TPI) was widely compatibilized with 12-Maghnite organo-modified clay. The results obtained by XRD, transmission and scanning electron microscopy (TEM and SEM) revealed that 1% (by weight) of the modified Maghnite was well dispersed in the polyurethane matrix. Thermogravimetric (TG) tests showed that nanocomposites could improve thermal stability. The gas permeability was examined by means of a membrane separation device. Significant improvements to the barrier properties were observed. The mechanical properties of the nanocomposites were evaluated according to the filler material used and the TPU matrix.Graphical abstract
... where K F denotes the Freundlich isotherm constant (L/g) and n represents the exponent of the Freundlich constant. When (1/n>1) the biosorption is unfavorable, when (1/n=1) the biosorption is homogeneous, and when (0<1/n<1) the biosorption is favorable (Bougdah et al., 2020). ...
Waste hazelnut shell was modified using hexadecyltrimethylammonium (HDTMA) to remove tetracycline and cephalexin from water and minimize the residual antimicrobial activity of tetracycline and cephalexin. Response surface methodology (RSM) was used to determine the effect of solution pH (3.0–6.0–9.0), initial pollutant concentration (5–52.5–100 mg/L), contact time (5–92.5–180 min), and temperature (20–35–50°C) on the removal efficiency of tetracycline and cephalexin. Comparison between model results and experimental data gave a high coefficient of determination (R²TC 0.94, R²CPX 0.99). The predicted removal efficiency of tetracycline and cephalexin by the RSM design was 37.34% and 83.07%, respectively. Langmuir, Freundlich, D-R, and Temkin isotherm were applied to equilibrium data. The Qo values for tetracycline and cephalexin were 6.97 and 47.77, respectively. Acute tests were performed before and after biosorption using Lepidium sativum and Daphnia magna. IC50, LC50, and toxic unit were determined. IC50 values for root and shoot for tetracycline and cephalexin were 50 mg/L, 50 mg/L, 140 mg/L, and 270 mg/L, respectively. LC50 values of tetracycline and cephalexin were 58 mg/L and 37 mg/L for 48 h, respectively. There was a large decrease in mortality (%) after biosorption. This biosorbent was effective in the biosorption of tetracycline and cephalexin and in reducing toxicity.
... The nonlinear form of the Langmuir, Freundlich and D-R models is presented in Eqs. (3) to (5), respectively [36,37]. ...
... The Langmuir, Freundlich and D-R parameters were calculated using nonlinear regression analysis of the corresponding models. Microsoft Excel solver and "trial and error" method were employed to calculate the parameters of equilibrium isotherms and minimize the error values [37]. The main characteristic of the Langmuir model can be calculated using a dimensionless constant (R L ): (6) where K L and C i are the Langmuir constant and initial concentration of formaldehyde, respectively. ...
Activated carbon (AC) was produced from date seeds by a calcination process at 700 °C for 2 h and then its surface was improved with CaO and magnetic nanoparticles. AC/CaO/Fe3O4 nanocomposite was then employed to remove formaldehyde ions from aqueous media. The structural characteristics of the materials were completely studied through FT-IR, XRD, SEM, EDX, Map, VSM, BET and TEM analyses. The results showed that the nanocomposite has a mesoporous structure (average pore diameter∼13 nm) with great sorption capability. Also, the utmost removal efficiency of formaldehyde using AC, AC/Fe3O4, CaO/Fe3O4 and AC/Fe3O4/CaO nanocomposite was 94.73, 95.67, 95.14 and 98.22%, respectively, indicating that the removal efficiency increases by improving the surface properties of the AC. Moreover, the uptake of formaldehyde using AC/Fe3O4/CaO nanocomposite follows the Freundlich isotherm and pseudo-2nd-order kinetic models. Furthermore, the highest sorption capacity of AC, AC/Fe3O4, CaO/Fe3O4 and AC/Fe3O4/CaO nanocomposite using the Langmuir model was obtained 19.86, 24.21, 21.28 and 24.01 mg/g, respectively. The thermodynamic study showed that formaldehyde sorption using all four adsorbents is exothermic and spontaneous. The reusability of the adsorbents was also evaluated after ten reuse cycles and the outcomes indicated that these four adsorbents have significant reusability. Moreover, the impact of interfering ions (e.g., carbonate, sulfate, phosphate, nitrate and chloride) showed that all of these compounds, except nitrate, had little competition with formaldehyde ions for adsorption on the nanocomposite surface.
... It has raised serious concerns because it is chemically stable, toxic, persistent, and bioaccumulative. The wide use of chlorobenzene in numerous industrial applications has led to its widespread release into the environment and consequent contamination of soil and water resources [4][5][6][7]. CB can accumulate in the human body through the food chain, causing many diseases such as cancer, teratogenesis, mutagenesis, anaesthetic effects, and can damage the central nervous system [8,9]. Because CB emissions have a strong negative impact on air quality and human health, increasing attention is being paid to its elimination. ...
... The sodium exchanged form of the bentonite (Na-bentonite) was prepared from Algerian natural bentonite according to the procedure described in our previous work [4]. To improve the adsorption capacity of natural bentonite, Na-bentonite has been modified with a cationic surfactant hexadecyltrimethylammonium bromide (HDTMA). ...
... To improve the adsorption capacity of natural bentonite, Na-bentonite has been modified with a cationic surfactant hexadecyltrimethylammonium bromide (HDTMA). The sodium-exchanged bentonite sample (20 g) previously modified using the ion exchange method was stirred magnetically for 48 h at room temperature with 200 mL of HDTMA aqueous solution [4,39]. The prepared HDTMAbentonite was washed with deionized water until a negative bromide test had been obtained with 0.1 M AgNO 3 (VWR Prolabo-chemical, Spain). ...
Prediction of adsorption capacity, one of the most important properties of any adsorbent-adsorbate system, is crucial for adsorption studies. In this investigation, two approaches such as multilayer perceptron (MLP) and random forest (RF) were used to predict the adsorption capacity of hexadecyltrimethyl ammonium modified bentonite to remove chlorobenzene (CB) from aqueous solution. The adsorption study was conducted in batch mode at different adsorption parameters. The results show that the adsorption processes were best described by Freundlich isotherm model, while the adsorption mechanism followed the pseudo-second order kinetics. It was observed that the structure of MLP model that give the best prediction consisted of three layers: input layer with four neurons, output layer with one neuron, and four neurons at hidden layer. The three important parameters for RF model were ntree = 500, mtry = 1, and node size = 1. According to the results obtained, the MLP model provided slightly higher levels of accuracy with a consistently high coefficient of determination (R2 = 0.996) and low root mean square error (RMSE = 0.00101) compared to RF model. (R2 = 0.969, RMSE = 0.03008). Therefore, the initial concentration of CB with 35.29%, appeared to be the most influential parameter in the adsorption of CB on the modified bentonite.
... The solution concentration allowed us to calculate the quantities q t (mmol g -1 ), q e (mmol g -1 ) and, R (%) [33][34][35]. ...
The development of effective methods for the processing of hazardous wastes containing chlorinated hydrocarbons still remains a big challenge. Herein, the approach allowing the transformation of chlorohydrocarbons into functionalized carbon nanomaterials was demonstrated for 1,2-dichloroethane (DCE) used as a model compound. Carbon nanofibers (CNF) doped with nitrogen and oxygen heteroatoms were fabricated by a joint decomposition of DCE and co-reagent (CH3CN, NH4OH, C2H5OH, and H2O). The Ni-Pd (5%) alloy was used as a catalyst precursor for the CNF synthesis. Pristine Ni-Pd alloy was found to undergo disintegration under the reaction conditions and to induce an active growth of the functionalized carbon nanofibers. The obtained CNF were shown to have a similar segmental structure of carbon filaments and to possess high specific surface area (up to 470 m²/g) and porosity (up to 0.9 cm³/g). According to X-ray photoelectron spectroscopy data, the nitrogen content within CNF samples prepared using N-comprising precursors was about 1.0-1.7 at.%. The total oxygen content reaches 3.6 at%. The obtained materials were demonstrated to be attractive for the dichlorobenzene adsorption from its aqueous solutions.
